Hi freddi,
Thanks for the additional information. In the 2" K-tube thread - http://www.diyaudio.com/forums/multi-way/282456-nice-k-tube-tweeter-6.html - I posted a drawing of the X15 from your sketches. There are no horizontal shelfs in the back or front chambers in that version (as in the sketches), is that correct?
Regards,
Thanks for the additional information. In the 2" K-tube thread - http://www.diyaudio.com/forums/multi-way/282456-nice-k-tube-tweeter-6.html - I posted a drawing of the X15 from your sketches. There are no horizontal shelfs in the back or front chambers in that version (as in the sketches), is that correct?
Regards,
there was no front nor rear shelf in my set of X15 - some had the rear shelf. Karlson only used the front shelf in K15 - perhaps also in his K18.
my X15 front with its orignal K-tube (tubes were sold to another party)
the triangular outline is where a previous owner attached screen with screen-door molding
3-panel reflector (concurrent with Karlson patent 3540544)
close up of K-tube
rear chamber view - no rear shelf in my X15 pair but Johny Holiday who posts
at the Klipsch forum has an X15 pair with rear shelf and 1.25" diameter K-tube
Some X15 had a rear shelf as with this model - I'm not sure but think this arrangement
might behave something like the later Acoustic Control 115BK, etc.
my X15 front with its orignal K-tube (tubes were sold to another party)
the triangular outline is where a previous owner attached screen with screen-door molding
3-panel reflector (concurrent with Karlson patent 3540544)
close up of K-tube
rear chamber view - no rear shelf in my X15 pair but Johny Holiday who posts
at the Klipsch forum has an X15 pair with rear shelf and 1.25" diameter K-tube
Some X15 had a rear shelf as with this model - I'm not sure but think this arrangement
might behave something like the later Acoustic Control 115BK, etc.
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- tb46 - that's a beautiful drawing of the X15 -
I don't think there was a rear shelf in mine - but will look again for evidence - seems like it would bump the highpass capacitor ? - then again seems like Karlson was fond of using them and there was one in Johny Holiday's pair of X15.
here's what I have on that speaker - I think GregB's Karlsonator and MMJ's Karlflex are good companions to consider and will go
lower than classic K12 or X15
Does X15's curved reflector exacerbate two ground plane dips? - or is that a problem with the small vent area? Those dips aren't seen on 115BK.
Carl's two variable slot calculation formula which I put into BASIC - X15 had a slot with P=1, Q=1.7 which opened a bit faster than a plain radial arc.
I can probably get screen shots of the expansion - if so, is there an increment in inches you would prefer?
The vent arrangement on my X15 with 5-de-Q-ing holes - I believe the K-tube's hole is perpendicular to the lower reflector panel (? - will check). It press fits into that hole then a 1 3/8" thread screw-on compression driver screws into a thick threaded phenolic block which is held to the lower reflector panel with 4 screws.
here is a copy of the X15 phenolic block - there's also a thin phenolic wafer which holds the sliced inner tube
I have somewhere a more descriptive version of this picture
Side view dimensions of my X15
Rough front dimensions of my X15
Rear Shelf on Johny Holiday's X15 - note the smaller diameter K-tube
I believe there were 8 de-Q-ing or distributing vent holes in this version
Johny Holiday's X15 K-tube - I'm guessing ~ 1.25" in diameter
I don't think there was a rear shelf in mine - but will look again for evidence - seems like it would bump the highpass capacitor ? - then again seems like Karlson was fond of using them and there was one in Johny Holiday's pair of X15.
here's what I have on that speaker - I think GregB's Karlsonator and MMJ's Karlflex are good companions to consider and will go
lower than classic K12 or X15
Does X15's curved reflector exacerbate two ground plane dips? - or is that a problem with the small vent area? Those dips aren't seen on 115BK.
Carl's two variable slot calculation formula which I put into BASIC - X15 had a slot with P=1, Q=1.7 which opened a bit faster than a plain radial arc.
I can probably get screen shots of the expansion - if so, is there an increment in inches you would prefer?
The vent arrangement on my X15 with 5-de-Q-ing holes - I believe the K-tube's hole is perpendicular to the lower reflector panel (? - will check). It press fits into that hole then a 1 3/8" thread screw-on compression driver screws into a thick threaded phenolic block which is held to the lower reflector panel with 4 screws.
here is a copy of the X15 phenolic block - there's also a thin phenolic wafer which holds the sliced inner tube
I have somewhere a more descriptive version of this picture
Side view dimensions of my X15
Rough front dimensions of my X15
Rear Shelf on Johny Holiday's X15 - note the smaller diameter K-tube
I believe there were 8 de-Q-ing or distributing vent holes in this version
Johny Holiday's X15 K-tube - I'm guessing ~ 1.25" in diameter
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Freddi's new horn cab
Freddi,
Sorry to hear that the new FLH is sounding strident, according to your graph the Altec is not outrunning it ..... Have you tried the new horn with just the LE-5 Tractrix to accompany?
Interesting that you would prefer a K-cab over the horn .... More great K-photos and information by the way! You are a treasure trove!
Freddi,
Sorry to hear that the new FLH is sounding strident, according to your graph the Altec is not outrunning it ..... Have you tried the new horn with just the LE-5 Tractrix to accompany?
Interesting that you would prefer a K-cab over the horn .... More great K-photos and information by the way! You are a treasure trove!
Hi Y'all,
I second that motion: "freddi is a treasure trove of Karlson information". Thank's freddi.
The X15 w/o additional shelves looks more like a BP6 w/ a Karlson aperture, that should be more forgiving than the K15, which looks more like a BP8(?).
After looking @ the nested K-tube in the X15 I tried slapping the 2"I.D. cardboard K-tube I made over the 1"I.D. fiberglass tube (using some acoustic foam pieces @ the bottom of the tubes as a spacer/holder), and I feel there may actually be an improvement, but w/ the junk piezo driving the K-tubes, and w/o measurements I don't even like mentioning it.
Regards,
I second that motion: "freddi is a treasure trove of Karlson information". Thank's freddi.
The X15 w/o additional shelves looks more like a BP6 w/ a Karlson aperture, that should be more forgiving than the K15, which looks more like a BP8(?).
After looking @ the nested K-tube in the X15 I tried slapping the 2"I.D. cardboard K-tube I made over the 1"I.D. fiberglass tube (using some acoustic foam pieces @ the bottom of the tubes as a spacer/holder), and I feel there may actually be an improvement, but w/ the junk piezo driving the K-tubes, and w/o measurements I don't even like mentioning it.
Regards,
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those 1188 or whatever the big piezo are with built in autoformer are pretty terrible sounding - IIRC - screechy like nails on a chalkbork
the new midbass horn is very smooth - I think I need to reduce the highpass cap to the old Univerity SAHF driver on the 511 to get it better - - - RCA-Fan thinks 511 are honky.
here's what's playing right now - it sounds as big as the horn on percussion and has very little cone excursion - but takes more input power - maybe its an illusion but it seems to be able to make good amounts of noise
Beta10cx/APT50 ~0.62 scale K15 - its got its coloration and Beta10cx may not be the most lively speaker from the getgo
do you think my old stiff LE5/250Hz tractrix is loud enough to keep up with the midbass horn? If I can find the right transformer
in my mess then could get maybe another 2-2.5dB by forcing the Z down against my XLS
the new midbass horn is very smooth - I think I need to reduce the highpass cap to the old Univerity SAHF driver on the 511 to get it better - - - RCA-Fan thinks 511 are honky.
here's what's playing right now - it sounds as big as the horn on percussion and has very little cone excursion - but takes more input power - maybe its an illusion but it seems to be able to make good amounts of noise
Beta10cx/APT50 ~0.62 scale K15 - its got its coloration and Beta10cx may not be the most lively speaker from the getgo
do you think my old stiff LE5/250Hz tractrix is loud enough to keep up with the midbass horn? If I can find the right transformer
in my mess then could get maybe another 2-2.5dB by forcing the Z down against my XLS
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Hi freddi,
I like the look of the .62x K15 in Post #1886, but I don't think I'm authorized to put that one in the living room. I have a few different ideas that might find government approval, which will have to wait until I'm retired (June 01, 2016).
Have you played w/ the miniDSP products any? That looks like the ideal solution for your matching problems. As to using the 511 horns, I used to use them w/ a 800Hz 2nd order crossover, and that removed quite a bit of the low end distortion, and it is almost imperative to mount the front horn flange solidly against something solid, otherwise the bell will ring; the last one I used I had inserted into a 1.5"thick baffle board, and caulked w/ silicone glue, and held w/ screws. This was in a studio environment, have never been able to get them authorized for living room use; maybe I should cut them like Emilar? I'm not familiar w/ your LE5 tractrix horn, but it won't stay w/ the midbass horn @ high levels, might sound great @ lower levels though.
Regards,
I like the look of the .62x K15 in Post #1886, but I don't think I'm authorized to put that one in the living room.
I have a few different ideas that might find government approval, which will have to wait until I'm retired (June 01, 2016).Have you played w/ the miniDSP products any? That looks like the ideal solution for your matching problems. As to using the 511 horns, I used to use them w/ a 800Hz 2nd order crossover, and that removed quite a bit of the low end distortion, and it is almost imperative to mount the front horn flange solidly against something solid, otherwise the bell will ring; the last one I used I had inserted into a 1.5"thick baffle board, and caulked w/ silicone glue, and held w/ screws. This was in a studio environment, have never been able to get them authorized for living room use; maybe I should cut them like Emilar? I'm not familiar w/ your LE5 tractrix horn, but it won't stay w/ the midbass horn @ high levels, might sound great @ lower levels though.
Regards,
- have not tried a MiniDSP - they look to do a lot for modest cost - - - I've got Emilar "bowtie" horns somewhere in my mess - very thick and relatively inert casting - sound great with higher xover. They need a baffle too to keep from losing low end.
FWIW I didn't see much distortion feeding an Altec 511 with w a cheap Selenium D250 trio wih 497Hz sine
I could probably squeak another 2.5dB from the JBL LE5/250Hz tractrix with an Edcor 25 volt transformer wired "backwards"
6=8 ohm, 8=4 ohm, 10 = v.c. common, 1 = 10W, 2 = 20W, 3 = 30W, 5 = line com.
FWIW I didn't see much distortion feeding an Altec 511 with w a cheap Selenium D250 trio wih 497Hz sine
I could probably squeak another 2.5dB from the JBL LE5/250Hz tractrix with an Edcor 25 volt transformer wired "backwards"
6=8 ohm, 8=4 ohm, 10 = v.c. common, 1 = 10W, 2 = 20W, 3 = 30W, 5 = line com.
Hi freddi,
Nice graph in Post #1888, it does show the ripple in the response increasing below 800Hz, the distortion is quite low though.
You are right, the 1188 piezos do have a spitting sound, the one I modified for use w/ the 1"I.D. tube (opened up the driver exit to ~ fit the tube) sounds much better than the unmolested driver on the PRV horn, talk about spitting.
I'll try attaching a picture again, maybe it'll work.
Regards,
Nice graph in Post #1888, it does show the ripple in the response increasing below 800Hz, the distortion is quite low though.
You are right, the 1188 piezos do have a spitting sound, the one I modified for use w/ the 1"I.D. tube (opened up the driver exit to ~ fit the tube) sounds much better than the unmolested driver on the PRV horn, talk about spitting.
I'll try attaching a picture again, maybe it'll work.
Regards,
Attachments
Modified Karlflex
Hi there.
I did some rework on the karlflex. I made s1 duct larger, starting at 13 cm at entrance, tappering to 8 cm, lenght 53 cm.
It helped a bit, sound is still somewhat pronounced in the 150-500 hz area. I also found out, that I probably have been to close to the speaker when listening, about 220cm, so I moved 1 meter further back and that helped too
Moving 1 meter back evened out the response and made it more coherent, but I would still have to use DSP EQ, to be satisfied.
I still have some ideas, for example, I'll try to put some other damping material right behind the speaker, right now it is glass wool and I think it might reflect to much sound.
With EQ the sound is powerfull and with good tone color, not to bad... Have to listen a bit more, to get a more precise review.
Cheers
Hi there.
I did some rework on the karlflex. I made s1 duct larger, starting at 13 cm at entrance, tappering to 8 cm, lenght 53 cm.
It helped a bit, sound is still somewhat pronounced in the 150-500 hz area. I also found out, that I probably have been to close to the speaker when listening, about 220cm, so I moved 1 meter further back and that helped too
Moving 1 meter back evened out the response and made it more coherent, but I would still have to use DSP EQ, to be satisfied.
I still have some ideas, for example, I'll try to put some other damping material right behind the speaker, right now it is glass wool and I think it might reflect to much sound.
With EQ the sound is powerfull and with good tone color, not to bad... Have to listen a bit more, to get a more precise review.
Cheers
Hooray for more progress!
Sebastian ,
Ohh good! I had a strong feeling that you would like the sound of a wider S1 section, helps damp the midbass somewhat .....
You might even like a bigger S1 yet, such as 13cm to 15cm all the way from top to bottom and stuffed ...
Listening distance from these cabinets can make a big difference indoors (especially) ... I am glad you are approaching something that is more acceptable sounding now ...
Do some snare drums still have the strange coloured clunk sound? I have to wonder if that is being caused by the large front chamber .....
I did manage to set up my Karflex12 outside today to be enjoyed by my neighbors hehehehe! (which i will write about in another post here in a few minutes) , but before i took it outside i made another measurement as the cab currently is tuned (FB=38hz) and compared it to the old Para-chambered Karlflex with 36hz tuning ...... I think you might have liked how the midbass was well behaved with the para-chamber , notice less hump at 200hz and less dip at 300hz (and i think the bump at 70hz was exaggerated due to the indoors measuring)...
This light Dayton 12 needed the higher tuning to get more presence between 40hz and 60hz (the final cabinet build should have smoother output between 200hz and 300hz according to Akabak)
Hi there.
I did some rework on the karlflex. I made s1 duct larger, starting at 13 cm at entrance, tappering to 8 cm, lenght 53 cm.
It helped a bit, sound is still somewhat pronounced in the 150-500 hz area. I also found out, that I probably have been to close to the speaker when listening, about 220cm, so I moved 1 meter further back and that helped too
Moving 1 meter back evened out the response and made it more coherent, but I would still have to use DSP EQ, to be satisfied.
I still have some ideas, for example, I'll try to put some other damping material right behind the speaker, right now it is glass wool and I think it might reflect to much sound.
With EQ the sound is powerfull and with good tone color, not to bad... Have to listen a bit more, to get a more precise review.
Cheers
Sebastian ,
Ohh good!
I had a strong feeling that you would like the sound of a wider S1 section, helps damp the midbass somewhat ..... You might even like a bigger S1 yet, such as 13cm to 15cm all the way from top to bottom and stuffed ...
Listening distance from these cabinets can make a big difference indoors (especially) ... I am glad you are approaching something that is more acceptable sounding now ...
Do some snare drums still have the strange coloured clunk sound? I have to wonder if that is being caused by the large front chamber .....
I did manage to set up my Karflex12 outside today to be enjoyed by my neighbors hehehehe! (which i will write about in another post here in a few minutes) , but before i took it outside i made another measurement as the cab currently is tuned (FB=38hz) and compared it to the old Para-chambered Karlflex with 36hz tuning ...... I think you might have liked how the midbass was well behaved with the para-chamber , notice less hump at 200hz and less dip at 300hz (and i think the bump at 70hz was exaggerated due to the indoors measuring)...
This light Dayton 12 needed the higher tuning to get more presence between 40hz and 60hz (the final cabinet build should have smoother output between 200hz and 300hz according to Akabak)
An externally hosted image should be here but it was not working when we last tested it.
OUTDOOR MEASUREMENTS AND LISTENING TESTS!
.... I turned it up and let my neighbors hear some A Perfect Circle, Tool, Pink Floyd and The Cure and various other random tracks but nothing too hard or edgy, i am trying to keep the peace with the nice folks who live around me
The cabinet sounds similar to how it sounded indoors but the bass output did sound more consistent no matter where i stood, it was nice being able to hear the Karlflex without the effects of bad room acoustics ....
Dynamics on drums sound as great outdoors as they do indoors, maybe even a little better ...
I made some random notes while playing a bunch of different tracks ...
Pink Floyd - Comfortably Numb = Well balanced mix, kick and snare sound excellent ..
Simple Minds - Don't You (Forget About Me) = great dynamics all the way around, lively and fun listening...
Tool -The Patient = Song starts off soft allowing me to turn it up for a mellow and neighbor friendly intro.. When the song finally kicks in it was a grand presentation! ..
CCR - Proud Mary = I never realized this song had a strong snare sound ..
The Cure - Burn = The Karlflex followed the drums on this track better than i thought it would .... Captured the soul of the track, i enjoyed it ..
I listened to dozens of songs and then had to get some measurements before the sun went down ...
This was by no means an ideal outdoor arrangement, but certainly better than trying to measure indoors .... I set up the cabinet on the pool deck and i had the swimming pool a few feet away from the cabinet on one side and a lossy grass lawn a few feet away in the other direction ..... No more than 3 or 4 feet behind the microphone was a chain link fence with slats in it which im sure was semi-reflective at higher frequencies (maybe accounts for the dip around 600hz) ...
Impulse response looks tight when measured outdoors
Here is my Outdoor @1m versus indoor @18" measurement ...
and the phase response , still not bad at all
.... I turned it up and let my neighbors hear some A Perfect Circle, Tool, Pink Floyd and The Cure and various other random tracks but nothing too hard or edgy, i am trying to keep the peace with the nice folks who live around me
The cabinet sounds similar to how it sounded indoors but the bass output did sound more consistent no matter where i stood, it was nice being able to hear the Karlflex without the effects of bad room acoustics ....
Dynamics on drums sound as great outdoors as they do indoors, maybe even a little better ...
I made some random notes while playing a bunch of different tracks ...
Pink Floyd - Comfortably Numb = Well balanced mix, kick and snare sound excellent ..
Simple Minds - Don't You (Forget About Me) = great dynamics all the way around, lively and fun listening...
Tool -The Patient = Song starts off soft allowing me to turn it up for a mellow and neighbor friendly intro.. When the song finally kicks in it was a grand presentation! ..
CCR - Proud Mary = I never realized this song had a strong snare sound ..
The Cure - Burn = The Karlflex followed the drums on this track better than i thought it would .... Captured the soul of the track, i enjoyed it ..
I listened to dozens of songs and then had to get some measurements before the sun went down ...
This was by no means an ideal outdoor arrangement, but certainly better than trying to measure indoors .... I set up the cabinet on the pool deck and i had the swimming pool a few feet away from the cabinet on one side and a lossy grass lawn a few feet away in the other direction ..... No more than 3 or 4 feet behind the microphone was a chain link fence with slats in it which im sure was semi-reflective at higher frequencies (maybe accounts for the dip around 600hz) ...
Impulse response looks tight when measured outdoors
Here is my Outdoor @1m versus indoor @18" measurement ...
An externally hosted image should be here but it was not working when we last tested it.
and the phase response , still not bad at all
An externally hosted image should be here but it was not working when we last tested it.
Matthew, that is a nice and even response you have got. If not for the dip at 600 it is very nice to +1000 hz
It shows that this design has potential and I will continue to pursue it
With that music choice, no neighbors can complain, just go for it
As you have seen I have got better sound with the new s1 mods. but not to my full satisfaction.
15cm s1, as you suggest, would barely leave room for the woofer and then potentiel backwave problems will increase...? But it is worth a try. Also experimenting with upper stubs, trying to block some of them, to make front ch. smaller.
The hunt for good Karlflex sound continues...
It shows that this design has potential and I will continue to pursue it
With that music choice, no neighbors can complain, just go for it
As you have seen I have got better sound with the new s1 mods. but not to my full satisfaction.
15cm s1, as you suggest, would barely leave room for the woofer and then potentiel backwave problems will increase...? But it is worth a try. Also experimenting with upper stubs, trying to block some of them, to make front ch. smaller.
The hunt for good Karlflex sound continues...
that's really good for the little PA310 - I think tb46's k-flex with tight K-aperture (post 1188) for 15pzb40 would play pretty much like Metro Systems' T15 with PHL15 bulk for bulk I'm not sure what pros and cons there are vs a simple reflex/MLTL as I think the low end would be similar other than a bit more active volume for the reflex (?)
I am enjoying this science
Yes , there is great potential here
Your experiments with the S1 modifications are VERY interesting! I think it is another thing that Akabak really doesn't fully clue us in on (significant tonal changes from S1 width adjustments)..
and good point about the 15cm s1 width, it would definitely bring the panel closer to the back of the driver's magnet, backwave reflections and the fact that we have to make sure the motor's pole vent can continue to breathe are things to consider..
I am looking forward to hearing the results of any s1 and front chamber stub experiments ...
I got away with it, no complaints, maybe i can go louder next time
I figured out that my dip in response that shifted from 300hz range (46cm mic distance) to 600hz range (100cm mic distance) is most likely related to "floor bounce" cancellation since my old para-chamber which is now blocked off is still a physical part of the box making the cabinet taller and putting the driver up higher than it normally would be with a standard Karlflex...
Here is a floor bounce calculator
https://mehlau.net/audio/floorbounce/
Matthew, that is a nice and even response you have got. If not for the dip at 600 it is very nice to +1000 hz
It shows that this design has potential and I will continue to pursue it
As you have seen I have got better sound with the new s1 mods. but not to my full satisfaction.
15cm s1, as you suggest, would barely leave room for the woofer and then potentiel backwave problems will increase...? But it is worth a try. Also experimenting with upper stubs, trying to block some of them, to make front ch. smaller.
The hunt for good Karlflex sound continues...
Yes , there is great potential here
Your experiments with the S1 modifications are VERY interesting! I think it is another thing that Akabak really doesn't fully clue us in on (significant tonal changes from S1 width adjustments)..
and good point about the 15cm s1 width, it would definitely bring the panel closer to the back of the driver's magnet, backwave reflections and the fact that we have to make sure the motor's pole vent can continue to breathe are things to consider..
I am looking forward to hearing the results of any s1 and front chamber stub experiments ...
With that music choice, no neighbors can complain, just go for it
I got away with it, no complaints, maybe i can go louder next time
I figured out that my dip in response that shifted from 300hz range (46cm mic distance) to 600hz range (100cm mic distance) is most likely related to "floor bounce" cancellation since my old para-chamber which is now blocked off is still a physical part of the box making the cabinet taller and putting the driver up higher than it normally would be with a standard Karlflex...
Here is a floor bounce calculator
https://mehlau.net/audio/floorbounce/
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That Hoffman is a filthy bastard
Freddi,
I always thought that the T-15 had a useful looking curve
It would not surprise me at all if TB46's Karlflex from #1188 performed just as well as the Metro cab especially if a similar front/back chamber ratio can be worked out .....
Standard Reflex/MLTL are 4th order while the Metro T-15, Karlsonator , XKi and Karlflex variants are all series-tuned 6th order cabs which according to simulations can have a size/extension advantage down around the fundamental tuning under certain circumstances ... The advantage can become apparent in sim when comparing TL(QWP) cabinets and Transflex (Tapped Pipe) cabinets of the same size and tuning with the same driver... So for example: Imagine a hypothetical scenario with a Transflex (Tapped Pipe) that is flat down to FB which is great, but the TL (QWP) with same dimensions and tune will have a humped overdamped contour and higher F3, therefore in order to get a flat curve the TL will need to be larger than the Transflex and if made large enough will outrun the other in terms of efficiency but at that point the TL is significantly larger, which is the compromise, Hoffman's Iron Law strikes again ...
Driver offsets as large as is used in the Karlflex can also be useful to reduce cabinet size and smooth response, but once again you run into Hoffman's Iron Law at every turn .....
Damn this Hoffman guy , what a jerk
NOTE: Regarding real world sound quality and satisfaction i can say from experience that removing the front panel from my Karlflex prototype converts it to a 4th order OD-MLTL and it sounds horrible set up in this way (as a 4th order) (and i don't expect a standard 4th order reflex to be any better, likely worse)...... To my ears the Karlflex set up as a 6th order cab (as it is now) sounds much much better, far superior!
ANOTHER NOTE: I like to think that i chose a very good set of compromises with the Karlflex but with such a compact cabinet and a lower tuning than the classic Karlson we cannot realistically expect to get the sort of gain that large horn cabs generate, I am just happy to get fairly flat response and good sound without EQ, and if i need additional output then more of these simple cabs can be built and loaded with affordable drivers. The dollar/decibel/packspace value works out well (in theory) especially since these can cover such a wide bandwidth
Freddi,
I always thought that the T-15 had a useful looking curve
It would not surprise me at all if TB46's Karlflex from #1188 performed just as well as the Metro cab especially if a similar front/back chamber ratio can be worked out .....
Standard Reflex/MLTL are 4th order while the Metro T-15, Karlsonator , XKi and Karlflex variants are all series-tuned 6th order cabs which according to simulations can have a size/extension advantage down around the fundamental tuning under certain circumstances ... The advantage can become apparent in sim when comparing TL(QWP) cabinets and Transflex (Tapped Pipe) cabinets of the same size and tuning with the same driver... So for example: Imagine a hypothetical scenario with a Transflex (Tapped Pipe) that is flat down to FB which is great, but the TL (QWP) with same dimensions and tune will have a humped overdamped contour and higher F3, therefore in order to get a flat curve the TL will need to be larger than the Transflex and if made large enough will outrun the other in terms of efficiency but at that point the TL is significantly larger, which is the compromise, Hoffman's Iron Law strikes again ...
Driver offsets as large as is used in the Karlflex can also be useful to reduce cabinet size and smooth response, but once again you run into Hoffman's Iron Law at every turn .....
Damn this Hoffman guy , what a jerk
NOTE: Regarding real world sound quality and satisfaction i can say from experience that removing the front panel from my Karlflex prototype converts it to a 4th order OD-MLTL and it sounds horrible set up in this way (as a 4th order) (and i don't expect a standard 4th order reflex to be any better, likely worse)...... To my ears the Karlflex set up as a 6th order cab (as it is now) sounds much much better, far superior!
ANOTHER NOTE: I like to think that i chose a very good set of compromises with the Karlflex but with such a compact cabinet and a lower tuning than the classic Karlson we cannot realistically expect to get the sort of gain that large horn cabs generate, I am just happy to get fairly flat response and good sound without EQ, and if i need additional output then more of these simple cabs can be built and loaded with affordable drivers. The dollar/decibel/packspace value works out well (in theory) especially since these can cover such a wide bandwidth
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Piano skill and driver quest
What a well played piece! Hofman definitely had some remarkable piano skills! Thank you for that, that was really nice , and it is not often that i listen to recordings from so long ago ...
I have been attempting to seek out more low cost 12" drivers for the Karlflex ...
I am not having much luck finding low budget drivers because motor strength is such a key factor here, and you generally don't get a lot of motor strength unless you spend some money, but i have found a few more drivers that are not too terribly expensive ...
The Eminence LA12850 looks like it should work well (although i wish it had more XMAX)
The PRV 12SW2000 also looks like a good candidate..
Also the JBL 2206 which can be picked up on ebay used for a good price..
I made a graphic:
What a well played piece! Hofman definitely had some remarkable piano skills!
Thank you for that, that was really nice , and it is not often that i listen to recordings from so long ago ... I have been attempting to seek out more low cost 12" drivers for the Karlflex ...
I am not having much luck finding low budget drivers because motor strength is such a key factor here, and you generally don't get a lot of motor strength unless you spend some money, but i have found a few more drivers that are not too terribly expensive ...
The Eminence LA12850 looks like it should work well (although i wish it had more XMAX)
The PRV 12SW2000 also looks like a good candidate..
Also the JBL 2206 which can be picked up on ebay used for a good price..
I made a graphic:
An externally hosted image should be here but it was not working when we last tested it.
